Mills said that the journalist who contacted her was not Morgan, who was editor of the Daily Mirror at the time of the alleged hacking. However, the facts she revealed appeared to dovetail with statements made by Morgan in a 2006 article in the Daily Mail.

In the article, in which he admits to hearing a recorded message which McCartney had left for Mills, Morgan said of the voicemail: "It was heartbreaking. The couple had clearly had a tiff, Heather had fled to India, and Paul was pleading with her to come back.

"He sounded lonely, miserable and desperate, and even sang 'We Can Work It Out' into the answer phone."

Discussing the tape later on the BBC's Newsnight, Mills said: "There was absolutely no honest way that Piers Morgan could have obtained that tape that he has so proudly bragged about unless they had gone into my voice messages."

At the inquiry today, Morgan said that he would not disclose any details about the "source" who had handed him the tape, despite Lord Leveson saying that it could only legally be supplied by Mills or someone she had given permission to do so.

When pushed, Morgan steadfastly refused to reveal how he had got access to the tape, and also denied that listening to it was "unethical".

He further pointed to claims previously made against Mills that she had leaked tapes to the press while married to McCartney.

However, Lord Leveson said that he may call Mills to see whether she had granted permission for the message to be listened to.

Morgan has consistently denied that hacking went on while he was editor of News of the World and The Mirror, and insisted that he has "never hacked a phone, told anyone to hack a phone, or published any stories based on the hacking of a phone".